"Forte 100 new" reciprocity failure?

Discussion in 'B&W: Film, Paper, Chemistry' started by Eugen Mezei, Oct 6, 2012.

  1. Eugen Mezei

    Eugen Mezei Member

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    Hello!

    I just have a roll of Forte (Fortepan?) ASA 100 in my Pentacon Six. I remember the box said "new", so it is the last emulsion (shortly before they get teared down).
    I wish to make some night exposures (illuminated church and statues) stopped down somewhere between f8 and f16. I expect a couple of measured exposure. How much I need to expose for the Schwarzschild effect?
    Unfortunately I can't find any tehnical papers for Forte. Maybe a table whit different reciprocity failure of films would be of some help too.
     
  2. BMbikerider

    BMbikerider Member

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    There is as far as I know no known guaranteed method of measuring reciprocity failure. It will vary to some degree from film to film and possibly batch from batch. The only reasonable way of guaranteeing the exposure is to bracket around the chosen apperture and when developed pick the one which is the best for you. Experience with one type of film will give you an idea how much to bracket.

    However exposures of up to a couple of seconds should not be affected. Reciprocity failure will not really kick in until around the 10 second mark. With colour film there are a whole set of other problems to contend with but B&W should be no problem.
     
  3. Shawn Dougherty

    Shawn Dougherty Member

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    I would save the Forte 100 for something else and get a roll of Fuji Acros 100 which has very negligible reciprocity failure characteristics and tons of available information. The Fuji 100 is cheap anyway (at least in the US) and will probably cost you less once you factor in the wasted time and frames trying to figure out reciprocity times for a film that isn't made anymore...

    Or... just bracket like crazy! =)

    All the best.
    Shawn
     
  4. Roger Cole

    Roger Cole Member

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    Cheap? Haven't priced it in 4x5, have you?

    One of the oddities of current pricing is that Acros is one of the least expensive films available in 120, and one of the most expensive in 4x5.
     
  5. chriscrawfordphoto

    chriscrawfordphoto Member

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    Regardless of cost, Acros is the BEST black and white film for long exposures. I've done exposures up to 5 minutes with it.

    [​IMG]
     
  6. Shawn Dougherty

    Shawn Dougherty Member

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    Yes, I have. The OP said he was using a Pentacon Six which takes 120 film and, as you say, Acros is one of the least expensive films available in 120...